'The Birth of a Nation' fumbles an important chapter of American history (R)

Review the execution of a work of art, not its intentions. That’s one of the hardest lessons a young critic needs to learn, and it applies to few films as much as Nate Parker’s “The Birth of A Nation.” Parker has made an uneven melodrama about an extraordinarily important subject: an 1831 revolt led by Nat Turner, the first significant attempt by an African American to free masses of fellow slaves.

We can lay praise or blame at Parker’s door: He makes his feature debut as writer-director, was a producer and plays Turner. The title rebuts D.W. Griffith’s 1915 film of that name, a racist Civil War drama and cinematic landmark whose narrative techniques are used today.

The name also suggests that our modern nation, where all men are free in principle if weighed down by social conditions, arose from this first violent attempt at equality. (Within 30 years, black soldiers fought in the Civil War.) Parker begins with a painfully timely quote from Thomas Jefferson: “Indeed, I tremble for my country when I reflect that God is just: that his justice cannot sleep forever.”

Parker might’ve done better simply to play Turner. He’s fine in early scenes, where the young man learns to read the Bible and exhorts slaves to trust God. He’s poignant as he witnesses horrible cruelty and begins to seethe, but he doesn’t have a fanatic’s fervor when Turner is messianic.

He goes wrong, though, by hammering his audience. After a poignant, silent scene in which Turner defies authority by baptizing a white man, his master (Armie Hammer) has him whipped. After the whipping, he rises with agonizing slowness to his feet, as a symphony orchestra and choir swell in approval. When Nat’s in jail, he grips the bars in the position of the crucified Christ, with light pouring in behind him.

A silent image of lynched blacks — men, women and children — freezes your blood. But it thaws as Nina Simone begins to sing “Strange Fruit,” underlining a moment that needed no emphasis with a song written 100 years later.

Parker overcompensates for Griffith’s racism by creating caricatures of his own. Except for Turner’s master, an alcoholic spendthrift with occasional beneficent impulses, every white man is a lecher, pervert, rapist, sadist or moron. Except for the master’s butler, a domesticated dandy played by Roger Guenvere Smith, all adult black characters are forbearing and devout. They may also be the least convincing field hands in modern cinema: perfect teeth, clear eyes and skin, manicured fingernails. That’s a bit more understandable in the house servants, including Nat’s wife (movingly played by Aja Naomi King).

Parker aims to give black characters dignity they’ve too rarely had in period films. Yet if you smash a man in the mouth with a rifle butt, he can’t have all his teeth and no scar afterward. No man, however brave, can turn his eyes to heaven and die in silent piety as a hangman chokes him slowly by pulling on a rope.

Details matter here more than in most movies. The world needs to know this story, and nobody’s going to tell it again for a long while. Parker put his heart and soul into it, but sometimes the road paved with good intentions doesn’t lead to Hell: It stops at mediocrity.